VirtualBox again

Due to reasons I swapped my web server (was in VM) and VM box role. Or more like web server is now bare metal and functions as VM box. It’s downgraded from real virtualization (Hyper-V) to VirtualBox though.

That said, FreeBSD doesn’t seem to be quite fully functional on Hyper-V thanks to performance hit and slow disk detection on boot causing failure.

Yeah, I’ve had enough of it so I decided to swap the role and run the web server directly on the server instead.

On the bright side, I can use zfs for everything and no more stupid SSD setup (it was unbalanced 500 and 250 GB disks).

VirtualBox seems to be flaky as always though apparently once it’s setup correctly it runs without much trouble. Also thankfully VirtualBox on FreeBSD has complete scripts for running it headless and autostart on boot.

This was also my main setup for quite a long time years ago and I sure hope it’s at least as stable as it was back then! That said, the initial setup seems to be flakier. Oh well.

Memo and stuff.

Rails and Bootstrap

This hit me when I was rewriting front-end part of Zeropaste. Of course later I found out that there’s gem for it.

But anyway, if you don’t want to add another gem and feel like writing crapload of divs, it’s not that difficult. It breaks Rails standard form error handling though.

First, change the default error field handling to do nothing instead of wrapping it in a div:

config.action_view.field_error_proc = proc { |html| html }

(put in application.rb)

And then create this helper:

def error_class(object, attribute)
  "has-error" if object.errors.include? attribute
end

Finally, here’s how to use it (for attribute key of a model):

<div class="form-group <%= error_class f.object, :key %>">
  <%= f.label :key %>
  <%= f.text_field :key, :class => "form-control" %>
</div>

…and done.

Network performance checklist: TSO/LSO

Took me good few hours to find out why specific combination of task performs incredibly slowly on my server.

For reference, in my case it’s port-forwarded ssh/https connection over openvpn.

[ Client ] --(Internet)--> [ Gateway ] --(OpenVPN)--> [ Server (SSH) ]

Doing anything which takes up bandwidth (displaying log files, etc) will shoot the cpu load (at interrupt) up by a lot. By a lot I mean over 50% of one core.

This guy have the reasoning why it’s happening but I don’t know how much of it is correct. VMware support page also suggesting disabling it if network performance is slow.

In FreeBSD it’s:

echo 'net.inet.tcp.tso=0' >> /etc/sysctl.conf

In Windows it’s this .reg file:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"DisableTaskOffload"=dword:00000001

It seems to involve a shell script in Linux so I won’t bother writing it off here since it differs by system.

As usual, YMMV.

…and there goes my time 🙁

dirlist-php

A few years ago I wrote a php script to provide better autoindex within nginx. I used it for quite a long period until I rewrote it in Ruby/Sinatra. But then I figured the setup for it is overly complicated just for simple task. And takes additional memory. I always have php-fpm running anyway so it’s free.

And so I decided to take up the old php script and fix it up. Unfortunately there isn’t other language as easy to setup for web as php which is why I fixed it instead of rewriting in some other languages (or keeping it ruby). The “fixed” version is still pretty much imperative-style but hey, it works.

Only tested with nginx.

Wasting time / 2048

2014-05-24 03.43.52

I’ve been wasting time on this thing called 2048 lately. And finally obtained my then-current goal of 8192. And then ended at 112k score since I wasn’t careful enough.

Next goal is 16384 but I’ll need to be able to reach 8192 without too much effort first…

PSA: Never trust external X-Forwarded-For

For god knows how long, proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; is one of the line usually included in nginx config snippet for proxying to a unicorn (Rails) backend.

…which is something you should never do unless you have another load balancer in front of the nginx being configured.

That line basically tells nginx to append $remote_addr to whatever X-Forwarded-For value currently set. It is only useful when your nginx is behind other load balancer which set up its own (hopefully correctly) X-Forwarded-For. It should be set explicitly to $remote_addr for any external-facing proxy. Otherwise fun things will happen.

FreeBSD pkg (manual) upgrade thingy

For working with locked packages (the ones which must be upgraded through compilation because of using custom options)

#!/bin/sh
# filename: pkg-lock-outdated

pkg query -e '%k = 1' %o | while read pkgorig; do
  pkg version -ovL => -O "$pkgorig"
done

The script above is to list locked packages which need upgrading. And to upgrade everything at once (and sit in front of PC waiting for whole process)

#!/bin/sh

listfile="/tmp/pkgforupgrade.$(date '+%Y%m%d%H%M%S')"
pkg-lock-outdated | cut -f 1 -d '<' > "$listfile"

while read <&3 outdated; do
  pkg unlock "$outdated"
  portmaster "$outdated"
  pkg lock "$outdated"
done 3< "$listfile"

rm -f "$listfile"

There’s another alternative of unlocking all packages at once, run batched portmaster, and lock them all again.

WordPress 3.5 Initial Impressions

This blog has been updated to WordPress 3.5. Initial impressions:

  • everything is less rounded now
  • Twenty Twelve (the new theme) sucks for following reasons:
    • uses custom font: causes this blog unreadable until fonts are loaded (at least in chrome)
    • image header: positioned below navigation menu (and the header text is above the menu)
    • no more search bar in navigation menu
  • the new media uploader looks useful

Overall there isn’t much change (what should I expect here) but the new theme sucks. At least to be used on this blog.